aenum --- support for advanced enumerations, namedtuples, and constants

aenum includes a Python stdlib Enum-compatible data type, as well as a
metaclass-based NamedTuple implementation and a NamedConstant class.

An Enum is a set of symbolic names (members) bound to unique, constant
values. Within an enumeration, the members can be compared by identity, and
the enumeration itself can be iterated over. If using Python 3 there is
built-in support for unique values, multiple values, auto-numbering, and
suspension of aliasing (members with the same value are not identical), plus
the ability to have values automatically bound to attributes.

A NamedTuple is a class-based, fixed-length tuple with a name for each
possible position accessible using attribute-access notation as well as the
standard index notation.

A NamedConstant is a class whose members cannot be rebound; it lacks all other
Enum capabilities, however; consequently, it can have duplicate values.

Module Contents

NamedTuple

Base class for creating NamedTuples, either by subclassing or via it's
functional API.

Constant

Constant class for creating groups of constants. These names cannot be rebound
to other values.

Note that Enum members are boolean True unless the __nonzero__
(Python 2) or __bool__ (Python 3) method is overridden to provide
different semantics.

Creating a Flag

Flag (and IntFlag) has members that can be combined with each other
using the bitwise operators (&, |, ^, ~). IntFlag members can be combined
with int and other IntFlag members. While it is possible to specify
the values directly it is recommended to use auto as the value and let
(Int)Flag select an appropriate value: